Method of and apparatus for making corrugated diaphragms



June 16, 1936. J 'G v MANTLE 2,044,711

METHOD 0F AND APPARATUS FR MAKING CORRUGATED DIAPHRAGMS Filed Nov. 11I 1924 2 Sheets-Sheet 1 u *EMEQEA wiwi June 16, 1936' JQ G. C. MANTLE 2,044,711

METHOD OF AND APPARATUS FOR MKIG CORRUGATED DIAPHRAGMS I lFired Nov. 11, 1924 2 sheets-sheet 2 l r l v INVENTOR ./Oselbv G. CMG/'1f le',y

' ATTORNEYS dPatented June 16, 1936 vPATENT orf-VICE METHOD F AND APPARATUS FOR MAKING CORRUGATED DIAPHRAGMS Joseph G. C. ltiantle, Leonia, N. 'J., assignorz by mesne` assignments, to Bridgeport Thermostat Company, Inc., Bridgeport, Conn., a corporation of Delaware Application November 11, 1924, Serial No. 749,208

14 Claims.

This invention relates to a method of and ape paratus for making expansible-contractible metal diminish .in thickness.

uti

*elements such as are adapted for use in pumps,

motors, or 1n pressure-sensitive or heat-sensitive4 devices in general. c

'I'he form of the article consists of a circumferentially-corrugated tubular wall having a closed end, the annular outer portion of lwhich end is of the same thickness as the tubular wall. and the central portion of this end being of appreciably greaterthickness, and the open end of the tubular wall being folded on itself and forming an outwardly projecting gasket-flange.

The article is manufactured by first forming a shell from sheetvmetal, then forming the outwardly projecting gasket-ange, and then converting the shell to its nal shape by placing the shell under internal pressure in a contractible mold and collapsing the shell while it is in the contractible mold.

Figures 1 to 5; inclusive, show the successive stages of the operation of forming the shell from Vsheet metal.

Figures 6 and 7 illustrate the start and the finish of the first stage of the operation for forming the outwardly-projecting gasket-flange.

Figures 8 and 9 show the start and the finish of the second stage of the operation for forming the outwardly-projecting gasket-flange.

Figure 10 shows the gasket-flanged shell after having undergone a, rolling operation.

`Figures 11 to 14, inclusive, show different forms oi the complete articles when converted into final shape.

Figure 15 is a view of a mold part used in forming corrugations. y

Figure 16 is a sectional view Figure 15.

Figure 17 represents a vertical section of a contractible mold with the grooved orrolled tube therein at the beginning of the forming operation; and

Figure 18 represents a vertical section of the contractible mold which has been collapsed t'o form the corrugated. tubular wall. y

Figure l shows the blank from sheetI metal, and winch is converted to shape, Figure 2, inthe first stage of the operation of forming the shell. It wili be noted that the closed ends of Figures 2, 3, i and 5 are all oi similar thickness, and that the tubular wallsA I, 2 and `3 (Figures 3, 4 and 5) The mannerland means for drawing the shell from theblank of Figure 1 is weli known and needs noexplanation..

through is-ls of `bounded by a wall l.

tained thereon by a washer Ill.

Referring to Figures 6 and 7,-a receptacle 3' has an opening 4 such that the shell may be slid therein. Adjacent this opening is an annular face 5 whichterminates in an` annular recess 6 The face, recess and wall serving as a former to form the outwardly-projecting gasket-flange, as may be seen in Figure 9. A plunger 8 has a reduced end 9, to which a washer Iis secured. Surrounding and secured to the plunger 8 is a counter bored ring II, the counterbore forming anannular recess for retaining the open end of the shell in position. It should be noted (Figure 6) that the open end of the shell but partially extends into the recess. Surrounding the end 9 and having a close slidin g fit thereon, is a sleeve I2, and which is re- Betwixt this sleeve I2 and plunger 8 is a cylindrical portion of compressible material, such as rubber, I3. Figure 6 shows the shell and apparatus at the start ofthe first stage of the operation of forming the outwardly-projecting*gasket-flange, and

Figure 7 shows the same at the finish. Upon the withdrawal of the plunger 8, the rubber I3 regains its original shape shown in Figure 6, and the shell has had its formconverted to that shown in Figure 8.

`Referring to Figures 8 and 9, a plunger N having a close sliding fit in the surrounding wall 1 of receptacle 3 has a reduced end i5 having a close sliding fit in the shell 3. 'Ihis plunger I5 in conjunction with the receptacle 3 serves as a former to complete the operation of forming the outwardly-projecting gasket-flange. Figure 8 shows the shell and parts of the apparatus at the commencement of this stage of the operation, and Figure 9 shows the same at the finish.

When the inner curves of the corrugations are nearer the axis of the diagram than the inner surface of the opening I6', then the shell is recessed inwardly, as is shown at I 6 in Figure 10 by a rolling operation. The manner and means for rolling these recesses is well known, and needs no explanation.

Either of the sheils shown in Figures 9 and l0 may be converted to any one of the final shapes shown in Figures 11, 12, 13 and 14, by using the hydraulic method disclosed in my application for Method of matting hollow articles Serial No. 726,671, filed July 18. 1924.

The grooved or rolled shell shown in Fig. 10 is adapted to be placed in an apparatus comprising a contractible mold, as shown in Figure 17 to con-n vert the rolled or grooved shell into corrugated shapefas shown in Figure 18. Thisvmold includes 4 a bottom mold part 32, a separable hinged top mold part 34, and a plurality of intermediate separable, hinged mold parts 20, 2|. The mold parts 20 and 2| are placed in the grooves` I6 of the shell or tube and are held together in this position by a Wedge or` cam projection 25 on one of the mold parts. A hinged mold part is shown in Figs. 15 and 16 and comprises parts 20 and 2| hinged at 22 and secured together by a, lever 23. The lever 23 is fulcrumed at 24 and is provided with the wedge or cam projection 25 adapted to engage member 2| of the mold part. The bottom mold part 32 is provided with a central depression or cutaway portion 36 upon which the closed end of the shell or tube is adapted to rest. The :flange of the shell or tube 30 is clamped between the top mold part 34 and the top holder 38. These two parts 34 and 38 are securely held together by screws or other suitable means.

Top mold part 34 and the intermediate mold parts 20, 2! are held in spaced relation by the interposed curved leaf springs 40, one end of each spring being connected to the bottom portion of the mold parts and the otheror free end of the spring being adapted to t in the slot 42 provided in the upper surfaces of each of the parts 20, 2|, and the bottom mold part 32. These springs 40 are adapted to permit independent -movement of each set of mold parts and to sustain the mold parts in correct relation to each other, and also act as guides in preventing lateral movement of the mold parts. The top holder 34 is provided with an opening 44, communicating with a pipe or tube 46 which telescopes into reservoir 48 containing fluid under pressure. Between the resel voir 48 and the top holder 38 is a removable stop piece 50.

After the shell or tube 30 is rolled or grooved, it is placed in the contractible mold, as vshown in Figure l'7 with the mold parts in the grooves I6. The flange of the shell or tube is then clamped between the top mold part 34 and top holder 38. The interior of the shell or tube is then subjected to uid pressure from the reservoir 48, and While the tube is under this pressure, the top plate 38 is forced downwardly to collapse the contractible mold and to form the corrugated tubular wall shown in Figure 18.

It can be readily understood that with a shell of given diameter and material, a deeper nal corrugation may be obtained by a prior corrugating of the shell, as shown in Figure l0. Also, as a rolling operation increases the hardness, a higher temper is induced in the corrugation nearest the axis. It will be seen that when the shell is placed in a contractible mold and subjected to internal fluid pressure there is an analogy to an uniformly loaded and equidistantly supported beam, and that the stress is greatest, and consequently the shell is thinnest and hardest, at the portions midway between the supporting surface of the mold parts of the contractible mold and is vthicker and softer the nearer it is to the mold parts. Now, the degree of this variation of hardness, due to the thinning of the material, is of course dependent upon the nature of the material and upon the applied pressure. Were the material soft pure rubber, there would be practically no variation in thickness. With low brass (low percentage of zinc) it is found that there is` but a Very gradual increase in thickness and decrease in hardness of the material from the outer to the inner corrugations, and that they are fairly uniform throughout their lengths. By the prior l rolling of the inner corrugations, as in Figure 10 the thickness of the material throughout the length of the corrugations is appreciably less than that of the original wall. The amount of this diminution is dependent upon the kind of material. It is found that brass consisting of 85% copper, 15% zinc, may be safely stretched fully 20%, or, in other words, until its thickness is about 83% o f its original thickness. 'I'his amount of stretch is well within its safe limit, for a series of diaphragms so made have already performed over 700,000,000 pumping operations (an extension and contraction), and are now apparently still in sound condition. The safe limit of circumferential stretch is dependent upon the chemical and physical nature of the material, chiefly upon the chemical. For the aforementioned kind of brass, it is about 50% of the original, and when the inner corrugations are primarily rolled as shown in Figures 10, 11 and 13, the circumference of the outer corrugations may be fully 60% greater than the circumference of the inner ones. This data is of value in determining the initial position of the mold parts with relation to their nal position, or, which is the same thing, in determining the spacings of the prior corrugations of Figure 10.

It is to be noted that the circumferential stretch (about 50%)-is greater than the longitudinal stretch measured along the corrugations which is but about 20%. This is accounted for by the axial compression (given by the axial movement of the mold parts) assisting the internal uid pressure in the circumferential stretch. It is obvious that for a given material when the limits of longitudinal and circumferential stretch are known, then all the possible forms of the corrugations of a diaphragm are easily determined. It must be remembered, however, that each particular material has its own values and which can only be determined (except very approximately) by actual test 0r experi-- ment.

It should be noted that the corrugations in Figures 11, 12, 13 and 14 are of different relative sizes and also shapes. With a given thickness of metal, the stiffness or resistance to extension and compression is increased as the radius of the corrugation is increased. It is still further increased by so forming the corrugations that their inner surfaces diverge outwardly from the axis of the diaphragm, as shown in Figure 12. In Figure 14 the alternate inner surfaces, only, of the corrugations diverge outwardly, and this is a useful form in a diaphragm pump for liquids, as it prevents the formation of air-pockets in the pumping chamber.

Referring again to Figures 11, 12, 13 and 14, it will be seen that th'e central portion of the closed ends have approximately the original thickness of metal and taper into the outer portionof the 6 lapsing the mold while the shell is under sustained internal pressure.

Referring to Figure 13, it will be seen that the entire closed end is not flattened out as is those shown in Figures 11, 12 and 14. To obtain this shape a much less fluid pressure is needed and the apparatus may be of a simpler formas not requiring a supporting surface for the outer sur' faces of the outer corrugations.

It is essential that the mold parts oftheconf tractible mold be held closely and uriyieldingly"` together, otherwise the internal -fluid pressure ingly held together. By inspection ofFigures 15 and 16 it will be seen that the two members 20 `and 2| are hinged at 22 and secured together by a lever 23, fulcrumed at 24, and that the lever is vprovided with a wedge or cam projection adapted to engage member 2| of themold part and hold it closely and unyieldlngly in contact wit member 2li.

In forming a diaphragm where the corrugations are required to be equidistant, it has been found to be unnecessary to provide means for positively controlling "the relative movements of the mold parts towards each other during the operation of forming the corrugations, but, when they are required to be very unequally spaced, or

'are cf varying forms, then such positively controlling means are necessary and the two member mold parts shown in Figure 15 is provided with lugs or other ymeans adapting it to be actuated by a control means to positively control the movei ment of the mold parts.

'2.1, 2B, v29 and 30).

In instances, among its various uses, where the diaphragm has to contain a high pressure uid,

the outer Surface of the inner corrugations are reinforced by supporting rings which maybe of any desired section as shown (in Figure 11, at

Of course, where the supporting rings are applied, Vthe shell isI not subjected to a prior rolling operation. They are supported and sustained in position by the mold- 'parts and for the time being form a part of the mold parts; but, they are not removable and they remain in position on the diaphragm, and thus constitute unitary parts of said diaphragm.

-'I'l'ie flexibility and amplitude of these diaphragms increases in proportion to'their diameters and in more than arithmetical proportion. The flexibility also increases as the depth of the corrugations. With a given form and size oi.' corrugation, the amplitude, viz. the difference in axial length of the diaphragm when extended and when compressed, varies in proportion to the number of corrugations. Attention is called to the uncorrugated portion next to the outwardly extending gasket-ange. Though increasing the axial length of the diaphragm. yet it is of value, for when the diaphragm is inverted and used in a pump connected with a gasoline or other -tankin which water is apt to enter, the water when drawn into the pump will sink and occupy a space adjacent the uncorrugated portion of the diaphragm and in the event o1 the freezing of the water will not interfere lwith the movements oi the corrugations nor in- It is to be understood that these diaphrag m s v may be made of any suitable material for the" purpose required.

Having thus fully describedthe invention, what I claim ras new and desire to secure by Letters 5 Patent is: l

,1.In`a'method of making metallic bellows, the steps which consist. in forcing spaced portions of a tubular 'metal wall `inward`to form inwardly extending corrugations therein, and then expand- 10 ing the tubular wall between said first-named' inner 4corrugations to form outwardly extending corrugations between said rst-named inner corin and around said tube with connecting sections of said tube between said grooves, and then acting upon said grooved tube to form it into a ilexible longitudinally expansible and contractible bellows.

3. The process of. making bellows consistingy in providing a plain elongated tube having a'thin wall, rolling' a series of spaced apart inwardly ex- 25 tending annular grooves with unworked and unchanged connecting sections of said tube between the grooves having the diameter of said tube, and then working said connecting sections to form outwardly extending corrugations from said con- 30 necting sections.`

4. The process of making bellows consisting in providing a plain elongated tube having a thin wall, forming a series of spaced apart inwardly extending annular grooves therein with uncorrugated connecting sections of said wall between the grooves, and then subjecting said connecting [sections to voperations which form outwardly extending corrugations from said connecting sections.

5. The process of making bellows consisting in providing a tube of thin metal, forming a series of inwardly pressed spaced-apart annular grooves in and around said tube with connecting sections having the diameter of the tube between said in'-l wardly pressed grooves, and then forming said connecting sections into outwardly extending corrugations.

6. The process of making bellows consisting in providing athin walled metal tube, rolling the metal of the tube inward to form grooves with connecting portions having the same diameter as the tube between said grooves, and forming said connecting portions into outwardly extending corrugations while enlarging the diameter of the same.

7. In the art of making a diaphragm embodying a circumferentially corrugated tubular wall and a head integral therewith, the process which consists in drawing the material into a seamless shell, then by a rolling operation forming circumferential recesses extending inwardly in the wall f of the shell, and then, whilst externally supporting said recesses and externally applying pressure to shorten the axial length of the shell, expanding the wall by internal fluid pressure to form circumferential corrugaticns extending from said recesses and outwardly beyond the wall of the ww shell.

u. The method of making articles from metal vshells or tubes, which comprises rol1ing.aplu

rality of grooves in the wall o1' a shell or tube, placing a plurality of mold parts in the grooves, and then collapsing the shell or tube while under the innuence of internal sind pressure to out- Cil wardly expand .the wall of the shellor tube between the grooves.

9. The method of making articles from metal shells or tubes, which comprises rolling a plurality of grooves in the wall of a shell or tube, arranging a plurality of mold parts in the grooves, applying pressure to the interior of the shell or tube, and then collapsing the shell or tube to expand the portion of the wall of the shell or tube between the grooves while maintaining an internal pressure.

f 10. The method of forming articles from metal shells or tubes, which comprises rolling a plurality of inwardly extending grooves in the wall of a shell or tube, placing the grooved shell or tube in a contractible mold, exerting pressure interiorly of the shell or tube, and applying axial external pressure to the shell or tube to forma corrugated shell or tube.

1l. The method of forming articles from metal shells or tubes, which lcomprises rolling a plurality of spaced grooves in the wall of a shell or tube, placing a plurality of mold parts in such grooves, applying pressure interiorly of the shell or tube and axially collapsing the wall of the shell or tube while under sustained internal' pressure to bring the mold parts together to form a corrugated shell or tube. y

12. A method of making expansible and contractible walls, which comprises, positioning a circumrerentially grooved tube or shell in a con- 5 tractible mold, applying internal uid pressure to the shell or tube, and then collapsing the contractible mold while the shell or tube is under sustained internal pressure.

13. A method of making expansible and contractible walls, which comprises, placing mold parts of a contractible mold in the spaced grooves of a circumferentially rolled tube or'shell, applying pressure internally of the tube or shell, and

then collapsing the tube or shell whllevthe tube l5 or shell is under sustained internal pressure.-

14. Apparatus for producing bellows tubing comprising a series of partible hinged die plates, the sections of each die plate having complementary recesses adapted to encircle the tube 20 when the die plate is closed', and yielding means interposed between the die plates on opposite sides of the tube-encircling recesses to preserve substantial parallelism of the die plates while permitting independent movement toward and from 25 one another.

JOSEPH G. C. MANTLE. 

